Stilbene oxide derivatives

This reaction proceeds with high ee using aromatic aldehydes such as benzalde-hyde (4.138) and derivatives using tosyl hydrazone salt (4.139) and thus has utility in the synthesis of enantiopure stilbene oxide derivatives. High ees are also obtained with some heteroaromatic aldehydes such as 2-furaldehyde (4.140). Basic heteroaromatic aldehydes are poor substrates and the reaction proceeds with low yield and/or diastereoselectivity using aliphatic aldehydes and most a,(3-enones as substrates. These limitations have been overcome using a stoichiometric variant of this process. 

Nakajima reported the use of a chiral bipyridine N,N -dioxide 18 in the desym-metrization of acyclic meso epoxides (Figure 7.3). Although the enantioselectivity was not as high as in the method developed by Fu for meso-stilbene oxide (90% ee vs. 94% ee), it was higher for the same aliphatic epoxide (74% ee vs. 50% ee) [57]. Nakajima showed that mono-N-oxide derivatives 19 and 20 were much less effective than 18 in tenns of both yield and enantioselectivity, and accordingly proposed a unique mechanism for 18 involving a hexacoordinate silicon intermediate coordinated to both N-oxides of the catalyst. 

Figure 7.14 Structural similarity between a biaryl derivative and nematic phase K15, and between Irans-stilbene oxide and the nematic MBBA.

S)-(-)-CITRONELLOL from geraniol. An asymmetrically catalyzed Diels-Alder reaction is used to prepare (1 R)-1,3,4-TRIMETHYL-3-C YCLOHEXENE-1 -CARBOXALDEHYDE with an (acyloxy)borane complex derived from L-(+)-tartaric acid as the catalyst. A high-yield procedure for the rearrangement of epoxides to carbonyl compounds catalyzed by METHYLALUMINUM BIS(4-BROMO-2,6-DI-tert-BUTYLPHENOXIDE) is demonstrated with a preparation of DIPHENYL-ACETALDEHYDE from stilbene oxide. A palladium/copper catalyst system is used to prepare (Z)-2-BROMO-5-(TRIMETHYLSILYL)-2-PENTEN-4-YNOIC ACID ETHYL ESTER. The coupling of vinyl and aryl halides with acetylenes is a powerful carbon-carbon bond-forming reaction, particularly valuable for the construction of such enyne systems. 

Kmeshy et al. [96], for the first time reported recyclable catalyst based on polymeric Cr(lll)(X) salen complexes derived from (lR,2R)-(-)-cyclohexanediamine with 5,5 -methylene di-3- erf-butylsalicylaldehyde and X = Cl, NO3, and CIO4 67-69 (Figure 22). These complexes were used in regio-, diastereo-, and enantioselective aminolytic kinetic resolution (AKR) of fra 5-stilbene oxide, trans- S- methyl styrene oxide, and 6-CN-chromene... 

In 1998, Yang and coworkers reported a series of (7 )-carvone derived ketones (63) containing a quaternary center at and various substituents at (Fig. 22) [119]. The ees of fran -stilbene oxide varied with different para and meta substituents when 63b was used as the catalyst. The major contribution for the observed ee difference is from the n-n electronic repulsion between the Cl atom of the catalyst and the phenyl group of the substrate. The substitution at also influences the epoxidation transition state via an electrostatic interaction between the polarized C -X bond and the phenyl ring on franx-stilbene (Table 6, entries 3-7, 10-14). In 2000, Solladie-Cavallo and coworkers reported a series of fluorinated carbocyclic ketones... 

The addition of anilines to styrene oxide was reported to also proceed in the presence of 10mol% 37 affording the corresponding P-amino alcohols 1-5 in yields ranging from 75% to 92% (Scheme 6.37). Additionally, urea derivative 37 (20mol% loading) was found to catalyze the addition of aniline (2.0 equiv.) to ( )-stilbene oxide (92% yield 5.9 d 30°C), the addition of thiophenol (2.0 equiv.) to 2-methoxy styrene oxide (85% 20h rt), and the alcoholysis of 4-methoxy styrene oxide with benzyl alcohol (2.0 equiv.) affording the respective P-alkoxy alcohol (82% 20h rt). 

The carbon fragment used in this approach can also be provided by sulfur yUdes. In this arena, Metzner and co-workers <99JCS(P1)731> developed a novel asymmetric variant employing (+)-(2/J,5/J)-2,5-dimethylthiolane (53) as the chiral auxiliary to prepare rrons-(S,S)-stilbene oxide (56). Chiral epoxides have also been prepared from aldehydes using sulfur ylides derived from the products of Baker s yeast reductions <99SL1328>. 

NOTE Higher nitrated derivs of Stilbene Oxide, such as Trinitro, C14H9N3O7, Tetra-niiro, CuHa Oo, Pentanitro, CuH NgOfi, and Hexanitro, Ci4HgNgOI3, were not found in the literature thru 1966... 

Stilbene Oxide. See under a,af-Diphenylethyl-ene Ether and Derivatives in Vol 5, D1457-R to D1458-R... 

Singlet as well as triplet excited states of oxiranes undergo C—C bond scission to produce carbonyl ylides which, upon cydoaddition with dipolarophiles, give tetra-hydrofuran (THF) derivatives. For example, trans- or ds-stilbene oxide on direct photolysis using 254 nm light in the presence of methyl acrylate gave diastereomeric... 

The reaction of stilbene oxide with a variety of aniline derivatives in the presence of indium triflate and the chiral bipyridine ligand 22 provided aminoalcohols in generally good yields and enantioselectivity <07SL2136>. 

Song / t/. have designed a series of structurally and electronically well-defined (72-symmetric chiral ketones 84-86 for use in the epoxidation of unfunctionalized olefins (max. 59% ee for /ra r-stilbene oxide) <1997TA2921>. Adam reported the synthesis and application of chiral (72-symmetric ketones 87 and 88, derived from mannitol and TADDOL, respectively, in the epoxidation of prochiral olefins (ee s up to 80.5%) (TADDOL = (-)-/ra r-4,5-bis(diphenyl-hydroxymethyl)-2,2-dimethyl-l,3-dioxolane) <1997TA3995>. 

This phase can be used in the preparative and analytical stereochemical resolution of a wide variety of compounds, including acetate derivatives of alcohols and diols benzylic alcohol derivatives pora-substituted d-phenyl-d-valerolactones 3,4-dihydro-2H-pyran-2-carboxylic acid derivatives phenylvinylsulfoxide fra s-stilbene oxide (46). 

The shortest synthesis of papaverine was achieved in the laboratory of R. Hirsenkom starting from racemic stilbene oxide and using a modified Pomeranz-Fritsch reaction The aminolysis of the stilbene oxide led to the formation of the cyclization precursor, which upon treatment with excess benzoyl chloride, underwent cyclization to give the N-benzoyl 1,2-dihydroisoquinoline derivative. Reduction under Wolff-Kishner conditions afforded papaverine. 

The results of studies described above have eliminated water from the solvent and O2 from the air as the source of the oxygen in the product of the main epoxidation reaction, and strongly indicated that the oxygen is derived from the oxidant directly. Closure is foimd in the complementary experiment in which the label resides on the peroxide. Epoxidation of cis- stilbene with 2% H2 O2 (90% enrichment of used as received due to cost) and open to the air resulted in 89.9 0.8% incorporation of in czs-stilbene oxide and 72.5 2.4% incorporation in frzzzzs-stilbene oxide (Scheme 3.11). The reproducibility is encouraging,... 

Arguments derived from conformational analysis were used73 to account for the fact that the ion 44 is generated in substantially higher abundance when threo- 1,2-diphenyl-l,2-bis(trimethylsiloxy)ethane (101) serves as precursor in comparison with the erythro-isomer (102). In the former both the cyclization step 103 - 104 and the elimination of trans-stilbene oxide (105) are favoured on stereochemical grounds (reaction 47). In the erythro-precursor 102, however, the destabilizing interaction of the two phenyl groups retards the formation of 44 (reaction 48). 

It is interesting to note that in vitro incubations of 1 with horseradish peroxidase [108] as well as with growing B. cinerea cultures [106] and B. cinerea culture medium filtrates [107] have yielded a unique resveratrol oligomer known as the resveratrol trans-dehydrodimer (42). This dimer shares a similar structural design with the more common plant-derived resveratrol dimer, f-viniferin (11). It has been proposed that the B. cinerea mediated transformation of 1 to 42 may be facilitated by other stilbene oxidizing enzymes such as copper-containing laccases [106,107]. 

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